1. Field of the Invention
The present invention relates to heat removal devices, and particularly to a liquid circulation cooler efficiently transferring heat from an electronic device.
2. Related Art
Computer electronic devices such as central processing units (CPUs) frequently generate large amounts of heat, which can destabilize operation and cause damage. Therefore, a cooler is generally placed in thermal contact with an electronic device to transfer heat from the electronic device through conduction.
FIG. 4 shows a conventional cooler for transferring heat from a CPU 100. The cooler comprises a heat sink 200 in thermal contact with the CPU 100, and a fan 300 fixed on the heat sink 200 to improve heat convection from the heat sink 200. The heat sink 200 is made of aluminum, and is formed by extrusion.
A ratio of a height of a heat sink to a width of spaces between adjacent fins of the heat sink is generally less than 13:1, due to inherent limitations of aluminum extrusion technology. This makes it difficult for the heat sink to meet the onerous requirements of heat transfer demanded by modern high-powered CPUs. With more and more heat being generated by modern CPUs, volume and weight of the heat sink are becoming greater and greater. Thus, it is becoming increasingly difficult to securely fix the heat sink onto a CPU. Furthermore, power must be consumed in order to operate a fan. Moreover, the fan produces noise when operating.
Accordingly, an object of the present invention is to provide a liquid circulation cooler which can efficiently transfer heat from an electronic device.
Another object of the present invention is to provide a liquid circulation cooler which has a small specific gravity.
A further object of the present invention is to provide a liquid circulation cooler which needs no power and produces no noise.
To achieve the above-mentioned objects, a liquid circulation cooler in accordance with the present invention comprises a body and a cover attached on the body. The body comprises a base having a first cavity accommodating liquid, a central hollow cylinder having a passage in communication with the first cavity, and a plurality of tubes extending upwardly from a periphery of the base and in communication with the first cavity. A plurality of fins extends outwardly from a periphery of the hollow cylinder. The cover defines a second cavity in communication with the passage and the tubes. The liquid within the first cavity is heated by a heat-generating electronic device and moved to the second cavity through the tubes by reason of temperature differences, gravitational force and capillarity of the tubes. Heated liquid which has reached the second cavity flows down through the passage along an inner surface of the hollow cylinder and returns back to the first cavity, by reason of gravitational force acting on the liquid. The heated liquid is cooled by the fins conducting heat away from the hollow cylinder when the heated liquid flows through the passage.